A wide range of temperature-indicating labels and monitoring devices from Dry Pak Industries, Los Angeles, provide quick visual assurance that quality control (QC) standards have been monitored during storage and transit of temperature-sensitive food, nutraceutical, pharmaceutical, diagnostic and electronic products.

Two types of temperature-indicating labels, reversible and irreversible, tell the current temperature of a product at a glance or indicate whether a critical temperature threshold has been violated. A low-cost, reversible label applied to the shipping carton or pail of confectionery and other temperature-sensitive foods allows QC managers to verify cold-storage conditions. These reversible labels use a liquid-crystal thermometer that indicates current temperature on the "green bar" section of the label. Reversible labels are also used in the medical-diagnostics industry to indicate temperature of specimens en route for laboratory analysis.

Dry Pak Industries offers irreversible labels that monitor conditions from -30 deg C to +300 deg C, as well as labels and tags that indicate how long a product has been exposed above critical temperatures. WarmMark[tm] and ColdMark[tm] Time Temp tags, used to monitor temperature during shipping and storage, are designed with three windows on the tag. Windows turn a tell-tale red as a product is exposed over or under critical temperatures for a brief time (30 minutes), a moderate time (two hours) or a prolonged time (two days). Typically placed on the outside of a pallet, irreversible tags and labels monitor temperature conditions as a product moves through the distribution system; up to 40,000 pounds of product can be monitored for less than $20.